New Gaia binary star measurements seem to support MOND and challenge dark matter

Yes, I read the report at phys.org too. Reference paper, Ref - Breakdown of the Newton–Einstein Standard Gravity at Low Acceleration in Internal Dynamics of Wide Binary Stars, https://iopscience.iop.org/article/10.3847/1538-4357/ace101, 24-July-2023. “Abstract A gravitational anomaly is found at weak gravitational acceleration gN ≲ 10^−9 m s^−2 from analyses of the dynamics of wide binary stars selected from the Gaia DR3 database that have accurate distances, proper motions, and reliably inferred stellar masses...A gravitational anomaly parameter δobs−newt between the observed acceleration at gN and the Newtonian prediction is measured to be: δobs−newt = 0.034 ± 0.007 and 0.109 ± 0.013 at gN ≈ 10^−8.91 and 10^−10.15 m s^−2, from the main sample of 26,615 wide binaries within 200 pc. These two deviations in the same direction represent a 10σ significance. The deviation represents a direct evidence for the breakdown of standard gravity at weak acceleration. At gN = 10^−10.15 m s^−2, the observed to Newton-predicted acceleration ratio is . This systematic deviation agrees with the boost factor that the AQUAL theory predicts for kinematic accelerations in circular orbits under the Galactic external field.”

The phys.org report does state: "The weak-acceleration catastrophe of gravity may have some similarity to the ultraviolet catastrophe of classical electrodynamics that led to quantum physics. Wide binary anomalies are a disaster to the standard gravity and cosmology that rely on dark matter and dark energy concepts. Because gravity follows MOND, a large amount of dark matter in galaxies (and even in the universe) are no longer needed. This is also a big surprise to Chae who, like typical scientists, "believed in" dark matter until a few years ago…Pavel Kroupa, professor at Bonn University and at Charles University in Prague, has come to the same conclusions concerning the law of gravitation. He says, "With this test on wide binaries as well as our tests on open star clusters nearby the sun, the data now compellingly imply that gravitation is Milgromian rather than Newtonian. The implications for all of astrophysics are immense."

I am amazed at the accelerations reported expressed in meters/second and distances out to some 200 pc or about 652 light-years using 26,615 wide binaries. It will be interesting to see what others measure and declare here as time goes by.
 
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They have distance, proper motion and "inferred mass". From that they calculate orbital period, then compare to actual. The discrepancy is due to MOND
A problem I see is the orbit period is used to determine mass. Then that is used to infer an ideal orbital period. Isn't this a circular argument?
 
They have distance, proper motion and "inferred mass". From that they calculate orbital period, then compare to actual. The discrepancy is due to MOND
A problem I see is the orbit period is used to determine mass. Then that is used to infer an ideal orbital period. Isn't this a circular argument?
Bill, I haven't tried to review the logic or math, so all I can speculate is that they did the usual mass inferences and then showed that there was a systematic problem with the results when the gravitational acceleration was very small. The article speaks of "wide binaries follow highly elongated orbits", so there may be some differences from Newtonian and Relativistic predictions of the apparent accelerations when the binary pairs are widely separated, compared to when they are more closely approaching each other? But, considering the data was collected during what could only be a very small part of the orbits of such widely separated stars, it does leave me wondering.

My thoughts were more along the line that there may be some sort of small systematic error in their process which only dominates the results when the gravitational acceleration is very small. They claim high confidence levels, but my experience has been that the uncertainty levels of most model results are generally underestimated.

The article states "I have also released all my codes for the sake of transparency and to serve any interested researchers." So, I will just wait to see what the experts in this field can find in the documentation.

Whatever the results of expert reviews and attempts at replication, this paper seems to have only the prospects for providing an important revelation to our understanding of gravity, or a grave egg-on-the-face moment for the researchers who claim such high confidence.
 
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Here is the problem:
I assume they use the speed of the orbit to tell them what the mass of the system is. I don't know how else to do it.
Then they use the mass of the system to tell them what the orbit should be.
Then they compare to actual.
Not enough independent variables.
They must have some other way of determining mass. Like maybe knowing the age of a star and how bright it is tells them mass. I don't know. I can't decipher the article.
 
BIll, I understand what you are saying. But, if they properly use the available info to compute their parameters, I would expect the results to match the theories used to make those computations, so there should be a verification of Newtonian or Relativistic theory, right? The fact that they are claiming non-agreement for specific parts of the orbits, where gravity acceleration is very low, seems to me to imply that there is something different somewhere. If it was only "circular logic", I would expect only agreement, rather than some non-agreement.
 
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I agree, circular logic would be identical. They must have another way of measuring mass. However, the differences they find are extremely small. They have error bars allright, but I am thinking back about the vanishing amount of excess heat they saw in cold fusion 30 years ago. It kept getting smaller and smaller. I also have a problem with it appearing only at very small g forces, coincidentally the same place the measurements are so tiny and fraught with potential sources of error.
Now I hear there are galaxies with no dark matter, no anomalous differential rotation problem. It gets more confusing.
 
If "dark matter" is simply regular matter that is not radiating photons (which was sort of the original idea), then it wouldn't be illogical for some galaxy to have a much larger than normal portion of its regular matter emitting radiation if there was some perturbation from whatever controls "average". Or, if dark matter really is something other than regular matter, then there may be different attractive or repulsive processes that could separate the two. I am not so sure that the measurements being made are really good enough to say there is zero dark matter in some galaxy, or what fraction of the galaxy's mass is emitting radiation we can detect.

It is just interesting to find something that is not already "explained" (rightly or wrongly) by the current theories, so that people really need to open their minds and think. That is how we make progress.
 
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